Milling machine



April 30, 1957 Filed May 10. 1954 P. P. M..DUBOSCLARD 2,790,360

MILLING MACHINE 4 Sheets-Sheet 1 -A. lllllilllllllllllll IN V EN TOR.

BY I" ATTORNEY- v x40 15101. RM. DUBOSCLAQD,

A ril 30, 1957 P. P. M. DUBOSCLARD MILLING MACHINE 4 Sheets-Sheet 2 Filed May 10, 1954 PAUL RM. DUBOSCLAIQD,

INVENTOR.

1 BY W l A TTORNE y.

April 30, 1957 P. P. M. DUBOSCLARD 2,790,350

MILLING MACHINE Filed May 10, 1954 4 Sheets-Sheet 4 19o BY AT TOQNEY.

United States Patent C fnfisginv'ehtidn'relatste a' ri improve 1 milling. m thine an jm'drf f particularly ltd a carriage for a milling t I illtateiniahiriinfgi of polygQhal'j cavitiesijm a vvqrlg" piece s ueh' as an integral spar used" in aircraft wiii'g constructio 'n. f

In r to meetthe requirements of" nevv" s'ig aircraft manufacturers have proposed t ture of integrated omponents of a'ri' aircraft st'i'u'etulfe.

integrated components is meant the substitution of one integral part for an assembly of a large'jn'umber ofsmjall parts", The, manufacture of such integrated com nen is xt'remel'y' desirable in order to achieve maximum f reduction in the aircraft structure per, se and to aid ra'tel'y produce" a desired aerodynamic esign; man'ufaeture of one integral member for a pre's'ently cons't mctediwing spar assembly n t only reduce time r'eciuiredfoi prodfiction of t a wing 'sp'a'rf, bnt jalsoir tip; a minimumpyramiding of errorswhi'ch adversely afieet aerodynamic design. p M w I v ,Jh' present invention contemplates amillin flmacnine for aeeiiratiely and rapidly machi n'ing polygonal; cavities "orkpiec'eland particularly for use in the q integral wing spar which, combines in ec' e' the prior a$sembly of two spar caps, the Web ,ext ding Eetwee'risaid 631 and stiffening ribs for said "web J Ihe pi'imary ohjeet of this invention 'islt o d rovide; afmilling rnaehih'e capable of machim ca m of dilfere'nt' siie, configuration and ldep'th in an integral vvdrli piejce' for producing an integral wingspan t Ai1 j9bject-of this} invention is'to dis'c'ld jjd" 1, n'iillifigmachine capable of finish machining ea'vitles in an integral wo'rk' pie e'. Y, nether ohieet of th i'sjinventien is jt'd di'sc f ide amilling machine" having a'e'afrriage ng to move alengfltli'e longitndinalaxis offlafw'orklpiec Whll'e'j mining" cutter ,is transve'rsely movable: with; rspt to" said aXisIand along a path at an angle thereto.-

A runner object ofthisinventionis to disclq I provide a milling machine wherein means are" provided for automatically reversing the directionof advancement of a carriage 'carrying a" milling cutter; t A' still further object of this inve'n tionis, to, diselose and provide a milling machine wherein rnea'n siar'ej previde'd' for facilitating milling" of cavities in' a workpie'ee, the'jc'avities having different levels. H Still another. objee'tl ofthis invention'is to di's closef and prjdvid "am inin macnine wherein a cutter is movable in' angular relationship tothe longitudinal axis ofi rnoye j ment of a carriage, traversing movement of, said cutter lieingj correlated to the rate of advancement of=the carriage; 65

Generally, speaking, this invention contemplates" millingmmhine' for, r'nillinglpolygonal cavities inan integral \vihg: spar" wherein a carriage is longitudinally movable along ajbedfwhieh supports a work piecevfr omtwliifihaa s rist obe rn"d e, The earriage'supp'drt ci l "e n s vvhic provides: way mea'nsi'eiitendiii ,f v7 x at an anglers- :6 the 6f the'be'dl A vertically mavu 2,790,360 Patent d; Apr. so, 1957 able 55311 head 'i "suaamy su parted on the cross-slide way'mga s fi n vernent therealon'g transversely and angula'rly df thevvo rk pieee. [The milling head is connected toa tracing arm arranged parallel to the, cross-slide Il S andlexjtending over a selected template bar template-naming man's positioned adjacent the s ts s 5w f i i i holding means along side sai'd bed; Fig "top vievv o'fthe carriage'and'template means sli o 'wniiiFig; I. W M I, tf iel tery; QntI of d'b i th e tria hqw i g ,3; g 1 G is a sectio'nalfview o'f the milling headl t'ak'en in .Yerticalfplan passing through the axis thereofl' Fig, 7 is anenla'rg ed, fragmentary view of limit means for controlling downwardrnovement of the milling head; Fig. 8 is a; fragmentary View of the templa'te and template' tiraeing'nieans taken from the plane indicated'by line VII1"V III of'Figij 3l' I Fig? 9 isanen'd vievv of a maehine emliddyiii g a modification of this invention" I 7 g I T Fig. 10 is a fragmentary side view ofthejmilling machih Shown in 9,*'the View take'ri f'lom the left'Of In Fig? Ian-exemplary; integral wing spar member .15 of a construction mac'hinedhy a milling machine" of this" invention 'is' illustr'ated'ahd" comprises top and bottbin sp'ai"cps' 16' EiiidIT joined a W Bb I Si extendingjfdi" the entire length of the spar member; A plurality of longitudinally spaeed transverse feihfor 'cing' rib s 19' exte'nd between the's'par caps and form therewith general 1y polygonal cavities 20 .of seleeted'sizeand sliapel The outer faces of spar cap'slfi and 17 provide surfaeeslte which a'-'metal" wing skin may he att'a ehe'di Preferably" the-outer and inner face'slpf 'eaehspa'r cap liefin'paiallel' planes to facilitate riveting of the faces of each spar cap maylie at an angle to the planeofi web 18 of thesp'ar member and such throughout the entireilen'gthof the spar member.

' In general, the milling maehi'ne of this invention, generally indicated at 25, may comprise a work p'ieee suppoit or bed 2'6'0f any suitable length, a'cai'ri'age means 27 mounted on said work piece support forlongitudinal' movement therealong, forwardly and angularly directed cross slide means 28 carriedby theflcarriage means', aver tically arranged milling head 29' slidably mountedon' the 7 Wing skin tothe spar member. The parallel planes of the outer and inner angle may vary which an exemplary spar member is to be machined. The work piece 33 may be rigidly secured to the work piece support in suitable well-known manner. The support includes a pair of laterally spaced parallel ways 34 and 35 for slidablysupporting carriage 27 thereon for movement of the carriage longitudinally along the work piece support and work piece. i I I V The carriage 27 may be provided with a downwardly facing longitudinally extending opening 41 adapted to receive work piece 33'and defined by spaced downwardly directed side members 42. Way engaging members 43 may be carried by thelower portion of each side member42. 1 Y Means for moving the carriage 27 and the cutting tool 30 longitudinally of the work piece support includes a pinion gearv 36 rotatable about a vertical axisat one side of thework piece support and enmeshed with teeth of a longitudinal rack bar 37 carried bythe work piece support. Means for driving the pinion gearj36 includes a vertical shaft 38 which extends upwardly to suitable gear means whieh'are driven by a motor means 40. The motor means 40 may be carried on top of carriage 27 and is reversible so that carriage 27 may be drivenin either longitudinal direction along the work piece support. 7

Means for moving the milling cutting tool 30 angularly with respect to the longitudinal axis of the work piece support may comprise the angularly and forwardly directed cross slide means 28 which may be rigidly fixed to thei'front portion of the carriage 27 in any suitable wellknownrnanner. The cross slide means 28 includes a structural member 44 of 'any suitable section illustrated in Fig. 6 as of box section.- The member 44 extends horizontally and at an angle-of approximately 45 to the longitudinal axis of the work piece support. The member' 44 may be provided'with top and bottom parallel front'fia'nges 45 and 46 respectively having secured thereto, as by welding, top and bottom rails 47 and 48 extending longitudinally of member 44 and above the work piece support. The rails 47 and 48 project above the flanges 45 and 46 and aiford cross slide way means for slidably supporting a block 49. The rail 48 may extend belowflange 46 as shown. The. slidable block 49 may include rearwardly extending top and bottom guide shoes 50 and 51 forming parallel guide grooves 52 and 53 adapted to slidably receive upper edge portions of rails 47 and 48. The bottom guide shoe 51 maybe integrally formed with the block while the top guide shoe 50 may include a detachably se cured guide element 54 to facilitate assembly and disassembly of the block from the rail 47. f, Theportion of the lower rail 48 extending slightly below flange 46 is adapted to be received within an upwardly facing guide groove 55 provided on;the bottom guide shoe 51. The groove 55 may be formed by a longitudinal element 57 releasably secured to the lower portion of guideshoe 51 to facilitate assembly and disassembly, of sliding block 49 with the rails.

The milling head 29 is mounted for adjustable vertical movement in sliding block 49. A vertically extending bore 60 formed in block 49 slidably receives an elongated tubular housing 61, said bore 60 being provided with top tending horizontal platform provided on the sliding block 49. The shaft 67 may be supported in bearing means 71 carried by a sidewardly extending portion 72 of the sliding block 49. The outer face of the portion 72 may adjustably carry an upstanding member 73 which carries a limit switch 74 adjacent its top having contact element 75 extending toward the shaft 67. The member 73 and limit switch means 74 may serve to limit downward movement of the milling head as later described.

The housing 77 of the motor means 65 may carry a sidewardly extending bracket 78 having asleeved bore 79 therein for sliding engagement with the shaft 67. Below the bracket 78 a loose square nut 80 may be threaded on shaft 67, said nut being held against rotation by abutment and bottominternal bearing means 62 and 63. The tubular housing 61 encloses a vertical drive shaft 64, the lower end of which carries the milling cutting tool 30. The uppere'nd of shaft 64 is coupled to the motor shaft of a motor means 65 of the milling head for rotating at selected speed, the milling cutting tool'30.

Means for vertical adjustment and positioning of the milling cutting tool 30 carried by the milling head may comprise a vertically arranged screw feed including a. vertically disposed threaded shaft 67 having --its axis parallel to the axis of milling head 29. The threaded shaft 67 may bedriven through a coupling means 68 by a motor means 69 carried on a suitable sidewardly exof one edge face against a depending sidewardly directed angle portion 81 of the bracket 78. The bottom face of portion 81 is adapted to contact the top of member 73 at the downward limit of movement of the milling head. The threaded nut, held against rotation serves to drive the milling head upwardly when shaft 67 is rotated. On downward movement of the milling head, the nut travels down the shaft and the milling head follows by gravity.

Means for facilitating positioning of a micrometric limiting stop for downward movement of the milling head 29 may comprise a vertically movable rack bar 83 carried by the sliding block on the side opposite to the shaft 67. The rack bar may be moved vertically by a suitable jack arm 84 carrying at its inner end teeth (not shown) for engagement with the bar ,83. The top face of bar 83 is contacted by a depending element 85 which is adjustably vertically moved by a handle 86 through micrometer means 87 for accurately precisely determining the limit of downward movement of the vertical milling head 29.

When ,the milling head is moved downward by the rotation of the screw shaft 67, abutment of the element 85 with the top of bar 83 will cause downward movement of the milling head to stop. Member 73 is vertically adjusted so that limit switch means 74 is positioned with its element 75 just below the selected downward limit of movement T of the milling head. The motor means 69 will then be stopped by reason of the nut 80 on the shaft 67 travelling downwardly in slidable contact with portion 81 and member 73 until it contacts the limit switch element 75 which then causes opening of the electrical circuit controlling operation of the motor 69.

Means for quickly raising the milling head 29 at the end of a cut and to assist-lowering of the milling head whenpiercing virgin metal may comprise a double-acting air cylinder means 89 carried by the sliding block 49 at the frontthereof, The air cylinder means 89 includes a reciprocal piston means having'piston rod 90 extend ing upwardly and secured to a lug 91 forwardly extendingfrom the-milling head. The air cylinder means 89 is actuated by a control means adjacent the template means as later described so as to cause immediate lifting of the milling head when desired.

The template means 230 comprises a suitable table 95 (Fig.3) which extends parallel to and adjacent the work piece support. A selected template 96 is carried on top of and along the inner portion of thetable 95 and may be accurately positioned thereon by template adjusting means 97 provided along opposite sides of the table. The exemplary template means 96 (Fig. 4) may comprise a plurality of longitudinally spaced polygonal openings98 of preselected shape and configuration. The polygonal openings 98 are defined by template edge faces 99 spaced slightly above the body of template 96 to facilitate positive engagement of the tracing means 31 therewith.

. The tracing means 31 for causing movement of the milling head and carriage in accordance with the pattern of template 96 includes a sidewardly and forwardly extendingtracing arm 100 illustrated as being of truss construction, rigidly fixed at its inner end to sliding block cally provided by the tracing means because a variation irrspeed of advancement of the carriage will vary the pressure contact of the stylus against the template along the edge B-C. Such variation in pressure will cause the tracing valve means to modify the flow of fluid to cylinder 112 in response thereto, and thus cause the sliding block to respond at the desired speed along the cross slide means. v v

Since this milling machine is designed tooperate at high speeds, as the stylus approaches corner C, the plate 117 contacts pin 116 which causes the plate 117 to rome and actuate a switch means 118 which. is electrically connected to the carriage longitudinal drive motor. Actuation of this switch means causes the carriage speed tolbe reduced. At reduced speed, the stylus isthen further advanced toward comerC until plate 120 contacts pm 119, said pin causing rotation of plate 120 so that it may contact a second switch means 121 for reversing the direction of the carriage drive motor. Since the advancement of the carriage forwardly has been reduced by actuation of the first switch means, the carriage will be stopped and commence movement in a reverse direction without overtravel of the cutting tool.

The carriage means and the milling cutting tool travel in an opposite longitudinal direction and the stylus moves along the edges CD and D--A. Movement along the edge CD is substantially the same as that described for movement of the stylus along the edge AB. Traversing movement of the stylus along the edge D--A is accomplished in the same manner as traversing movement along the edge B-C, the speed of traversing movement being in the order of the square root of 2 times the speed of movement of the carriage means.

As the stylus approaches the corner A, the operator prepares to stop longitudinal movement of the carriage 7 means and to raise the milling head and the cutting tool from the work piece. When thestylus reaches corner A, the carriage feed is automatically stopped when the operator lifts lever 122. Atthe same time lifting of lever 122 causes the air cylinder means 89 to raise the head. After the cutting tool has been raised from the cavity, the carriage means may be longitudinally advanced and the cutting tool lowered for commencement of cutting of an adjacent cavity in the work piece. j

In the event the cavity to be cut includes different contours at diflferent levels of metal, the operator may readily change to such different levels by rotating the tracer arm 107 about its swivel mounting 106 so thatthe stylus 111 may contact and be responsive to the template edge on the adjacent template means 96'. The cooperable relation of the stylus 111, cutting tool 30 and tracing valve means 110 with respect to the template 96' is the same as that described for the template 96.

In Figs. 9 and is shown a different modification of this invention wherein a work piece is held in a vertical plane, a template is held in a spaced vertical plane, and a carriage is movable between the spaced planes of the workpiece and the template. Also in this modification, the milling cutter is rotatable about a horizontal axis and cross-slide means is arranged for movement in a planeinclined to the horizontal at approximately, 45. The operation and control means of the milling machine of this modification are substantially the same as the prior embodiment and only differences in construction will be described in detail.

In this modification a bed 130 may be provided with spaced parallel way means 131 and 132 for movement of a carriage means 133 longitudinally along the bed. The carriage means 133 may be provided with a downwardly facing longitudinal opening 134 within. which may be received a longitudinally extending rack 135' carriedby the bed and engaged by apinion 'gear136 rotatable'about avertical axis. The pinion gear may-be connected by a yer-ticalshaftulfl to a reversible longitudinal drive-motor 138 mounted on platform provided therefor on the rear of the" carriage 133.

, Extending along one longitudinal side of bed may be awork piece support means 139, said work-support means having atop rem'ovablework-support member 140 for carrying a work piece 141. The work-support member 140 may-beprovided with a vertical planar surface facing the carriage means 133 upon which the work piece 141 may be supported in any suitable well-known manner. Along the o'p'posite longitudinal side of bed 130 may be provided a template support means 142v which may also be disposed in a vertical plane parallel to and spaced from the plane of'the' work 141. Suitable horizontal members 143 may be provided for supporting the template means 142 in spacedrelation to the side of bed 130 for providing suitable clearance for the carriage means 133. The template means 142 may carry on its outer face a suitably selected template 144 disposed in a vertical plane and secured thereto in any well-known manner. The template 144 is provided with a template edge 145 having a desired contour for a cavityto be milled in the work piece.

: Thecarriage means 133 is provided with a forwardly and downwardly inclined cross-slide means 147 which may include parallel longitudinal ways 43 inclined at an angle approximately 45 to a horizontal plane. A sleeve-block means 149 may beslidably mounted on the cross-slide means 147 for movement therealong. The sleeve block 149 is provided with a horizontal transverse bore 150 in which maybe slidably mounted for horizontal axial movement a tubular member 151 of a horizontal milling head 152. The tubular member 151 carries at its extremity a milling cutter 153 for rotatable cutting engagement with work piece 141.

' Means for slidably moving the sleeve block 149 along the 'cross-slide'means 147 may include a forwardly and downwardly inclined double-acting hydraulic cylinder means 155 carried at the top of carriage 133. The cylinder means 155 is provided with a piston rod 156 at its free end to the sleeve block 149.

Means. for moving the cutter 153 horizontally may comprise means sirnilar in' constructionand operative to that disclosed in the prior modification. Attached to sleeve block 149 may be a horizontal milling head feed motor 158 having a screw feed shaft 159 provided with a loose travelling nut 160 which may engage a bracket 161 carried by the milling head 152. Also attached to the sleeveblock 149 may be a double-actin'g air cylinder means 162 provided with'a piston rod 163 connected to the bracket 161 attached to the milling head 152. The air cylinder means 162 and screw feed 159 driven by motor 158 serves to horizontally adjust the milling cutter with respect to the vertically disposed work piece, the operation and'control thereof being virtually the same as that described for adjustment of milling head 29 of the previous embodiment.

Tracing means is arranged similarly to that described in the prior embodiment and may include a downwardly extending tracer arm 165 carried by the forward face of sleeve block 149 and extending to and disposed on the outer side'of the template means 142., The tracing arm 165 may carry at its end a tracer valve 166 having a tracer pin 167 for cooperable responsive engagement with the contour edge 145 of a template 144. If desired, polygonal; plates 168 and '169 may be provided to auto.- maticallyjcontfol movement 'of the tracer pin 167 along two contiguous edges of the template 144 while the car? triage is moving in one direction as described in the prior embodiment The tracer arm 165 maycarry a retracting lever 17!} which is cooperablyassociated with a limit 'switchl means 1 7 1 for'inoving the cutting tool but of ,contactgwiththework piece all as described in detail in thepriorembodimcnt. c It will bereadily apparent in this modification that the horizontally disposed cutter 153 may move along a work piece 141 in the direction of travel on the carriage and while the carriage is advancingat aselected rate of speed may also move in a vertical direction to cut to the conwork piece wherein the carriage'means is movable along a selected path, a cutter means is movable along a path lying in'a planeperpendicular to the direction of movement of the carriage means, and the cutter is also movable along'a path lying in aplaneat-an angle to the path of thecarriage means. It isunderstood of course that for the plnposes of thismodification the template may be mounted in difierent manner; In each embodiment shown, the carriage means is provided with cross slide means for advancing a cutter at "an angle to the direction of movement ofthe carriage means.

The milling machine of this invention thus provides a novel carriage means for finish'machining of cavities in a work piece which includes cross-slide means for the milling head arranged at an angle to the longitudinal direction of movement of the carriage and whereby two contiguous faces of the cavity may be machined while the carriage moves in one direction. It is important to note that the carriage feed is automatically stopped and reversed and that over travel of the cutting tool is positively prevented. Template changes are minimized by the particular arrangement of a swivel mounted tracing arm which can be readily engaged with a difierent template.

All changes and mo dificationscoming. within the scope of the appended claims are embraced thereby.

I claim:

1. In a machine for milling cavities in a work piece, the combination of: a work piece support; a carriage movable along said work piece support; cross-slide means on" the carriage including ways arranged at an angle to the direction of movement of the carriage along the support; a block slidable on said ways; a milling head carried by said block and provided-with. a'vertically-adjustable milling cutter; means carried bysaid cross-slide means and connected to said block for moving said block; means for moving said carriage; template means adjacent said work piece support; and single tracing means on the cross-slide means cooperable with said template means and controlling said carriage-moving means and said block-moving means for causing traversing movement of the block during movement of the carriage to move the cutter at virtually constant cutting speed in at least two directions.

2. A machine as stated in claim 1 including means on the template means cooperable with said tracing means for reversing the direction of movement of the carriage.

3. In a milling machine for machining substantially rectangular cavities in a work piece, the combination of a work piece support; a cutting tool; means for moving said cutting tool in a direction longitudinally of the work piece; means including a forwardly and angularly directed slide means mounted on said moving means for simultaneously moving said cutting tool at an angle to the longitudinal direction of movement of the cutting tool; means for controlling the rate of movement of said cutting tool in both longitudinal and angular directions whereby two contiguous walls of the cavity may be machined at virtually constant cutting speeds in both directions during longitudinal movement of the tool in one direction; and means for reversing the direction of longitudinal movement of the tool for machining the opposite contiguous port at one side orsaidbed; a t

i in walls orthe: cavity dur ing 'lohg'itudinal movement of the tool in the opposite direction.-

4. In a milling mac the combination or; awork piecesnpport tor carfying a were piece in averticarplan;

responsively engaging-maid templatefor co'ntiollin'g traver'singmovementof the riiillirig head on 'the' slide means during movement of the carriagei 5. Ina milling machine for-niachili"'gfcavities'in a work=piece,-thecombination of abedi a work 'iecesap- 7 plate support-at the opposite side of said bed; a cuttin-g tool between: said-work piece support and said templa'tesupport; ine'ansfo'r moving said c'utting'tool in a directionlongitudinally of-the work piece; means for moving -said cutting tool towards and away from said-"work piece-support; means-tor moving. said 'cuttingitoo l at an angle to the longitudinal direction of movementof the cutting tool; and tracing means operably associatedwith atemplate carried by the template support Inean'sand with the cutting tool.

6. In a milling machine tor rni l-ling cavities in-a work piece, the comb'in'a'tion of: a bed; a carriage man'siitoJ- able longitudinally along-said bed; awor k piece su'ppor't extending along one sided said bed a nd' adapted to support a "work piecein "a verti'ca'l lane; a templat'e support means carried by tlie bedon the other side thereof and adapted to support a= templatein a vertical plafispaced from the plane of the work piece support' 'a horizontally disposed: milling lteacl 17ndmi-ted on said carriage means and having a cutter 'r'otat'able ahout a horizontal axis' aiid disposed a'djace" said; w'ofk icesupportjand means for moving sai'd millinghead along a pat-h'in'cline'd to the vertical. I

7. In a milli-ng rri acliihe -as-defined in claim 6 wherein the means' foi 'moving sfa-id niilling nead alnnan inclined path-includes p'a'fiallelincli-ned way meahs on said carriage means; I

8. In a millingmachinefas defined in claim '6 wherein said carriage rnea'nslincliides a forwardly facingxdownwar-dl y inclined wa means; a sleeve block slidably mounted on said inclined way means for carrying said milling head; and a tracing means extending forwardly and downwardly from said sleeve block for cooperable association with a template means.

9. A carriage for a milling machine to move longitudinally along an axis of a work piece support and including cross-slide means on the carriage provided with means provided on the carriage anddisposed in oblique relation to the path of movement of said carriage; a mill ing head slidable along said cross-slide means; and tracing means connected to the milling head and supported by said carriage, extending parallel to and beyond said-cross-slide means, a

tracing assembly mounted at the end of said arm and inj cluding a tracing stylus adapted to engage an associated template means, a switch means carried by the tracing assembly and connected to the drive means; and a polygonal plate pivotally mounted on said tracing as said tracing means including a tracing arm sembly for contacting said switch means to reverse the direction of movement of said carriage.

12. In a machine as stated in claim 11 wherein said tracing assembly is pivotally mounted at the end of said tracing arm.

13. In a milling machine, the combination of: a carriage; means to move the carriage along a path at a selected constant speed; a cutting tool; means to support the tool from the carriage and to move the tool along a path oblique to the carriage path; and means for correlating movement of the tool in the oblique path and the carriage path to maintain virtually constant longitudinal and traverse cutting speeds with virtually constant speed of the carriage in one direction, said correlating means including a single tracing means cooperably connected to said tool moving means. e

14. In a milling machine, the combination of: a carriage; means to move the carriage along a path at a selected constant speed; a cutting tool; means to support the tool from the carriage and to. move the tool along a path oblique to the carriage path; and means for correlating movement of the tool in the oblique path and the carriage path to maintain virtually constant longitudinal and traverse cutting speeds with virtually constant speed of the carriage in one direction, said correlating means including single tracing means comprising a tracing arm extending parallel to the oblique path. 1

15. A milling machine as stated in claim 14 wherein means at the end of said tracing arm are operatively connected to the carriage moving means to automatically reverse the direction of movement of said carriage.

16. A milling machine as stated in claim 15 wherein said automatic reversing means on the tracing arm includes a switch means and a pivotally mounted plate, and a pin on an'associated template means to cooperably engage said plate.

17. In a milling machine, the combination of: a carriage; means to drive the carriage along a path at a selected speed; a cutting tool; means to support the tool from the carriage and to move the tool along a path oblique to the carriage path, said support means including an obliquely extending cross-slide means fixed on said carriage; and a single tracing means connected to the tool moving means and carried at the extremity of said cross-slide means to correlate movement of the tool in the oblique path with carriage movable longitudinally of the workpiece support; means for driving said carriage; a milling head; slide means on said carriage slidably supporting said milling head for movement along a path at an angle to the longitudinal movement of the carriage; means on the carriage for moving said milling head; template means adjacent to the workpiece support; and a single tracing means carriedby the slide means responsively engaging the template -means for selectively correlating the rate of movement of the milling head on the slide means with longitudinal movement of the carriage whereby contiguous walls of a cavity being machined may be cut at virtually constant cutting speeds.

. 19. In a milling machine, the combination of: a workpiece support and a template support means lying in parallel relation; a carriage longitudinally movable parallel to the workpiece support; a milling head provided with a milling cutter for cutting engagement with a workpiece supported by the workpiece support; and means for mounting said milling head on said carriage for movement along a path at an angle to the longitudinal direction of movement of the carriage and including tracing means positioned at an extension of said angular path and cooperably positioned with respect to said template support means. v

20. In a milling machine for machining cavities in a workpiece, the combination of: a workpiece support; a

cutting tool; means for moving said cutting tool in a directionlongitudinally of the workpiece; means including an angularly disposed slide mounted on said moving means for simultaneously moving said cutting tool at an angle to the longitudinal direction of movement of the cutting tool; and means for controlling the rate of movement of said cutting tool in both longitudinal and angular directions whereby contiguous walls of a cavity may be machined at virtuallyrconstant cutting speeds during longitudinal movement of the tool in one direction.

.References Cited in the file of this patent UNITED STATES PATENTS 2,059,505 Wright Nov. a, 1936 2,341,194 Schwartz et a1. Feb. 8, 1944 FOREIGN PATENTS 519,102 Great Britain -Q. Mar. 15, 1940 i 740,122 France Jan. 21, 1933 1,072,582 'France Sept. 14, 1954 

